Apparatus for drying slurry and other materials



Allg. 9, 1938. 1 ,t DfpARKER 2,126,029

APPARATUS FOR DRYING SLURRY AND OITHERA MATERIALS Filed Oct. .'51, 19352 Sheets-Sheet 1 Aug# 9, 1938. L. D. PARKER 2,126,029

APPARATUS FOR DRYING SLURRY AND OTHER MATERIALS Filed Oct. 5l, 1955 2Sheets-Sheet 2 UNITED STATES PATENT FFICE y APPARTUS FOR DRYING SLURRYANI)l OTHER MATERIALS Lionel Douglas Parker, Barrow-in-Furness,

England, assignor to Vickers-Armstrongs Limited, Daily Westminster,England, a British com- Application October 3,1, 1935, Serial No. 47,605

. In Great Britain November 13', 1934 12 Claims.

from a cement kiln are caused to pass diametri-` cally through the saiddrum. Such an arrangement is not altogether satisfactory since, in therst place, the fact that the filling bodies rest during rotation of thedrum upon the lower surface thereof produces an unbalanced` load whichdecreases the mechanical emciency and increases power consumption.Furthermore, an appreciable proportion of the kiln gases and cement dustcarried along thereby are deflected by the surface of the drum and arethus caused to pass between the periphery of the drum and the innersurface of the surrounding casing, and are therefore wasted, whilst ifthe cement dust is to be reclaimed a special extraction apparatus orseparator is required. Also in this prior proposal it is important thata uniform ilow of slurrry should occur in order to avoid agglomerationor caking of the slurry, particularly on the surface of the drum. Inaddition it is necessary to maintain the drying gases at a substantiallyconstant temperature, otherwise the dried-or partially dried materialpassing from the drum along a chute to the kiln is liable to cake oragglomerate on the surface of the chute.

It is the chief object of the present invention to provide an improvedapparatus for drying slurry and other materials, (particularly cementslurry) Witha view to avoiding in the preferred form of the inventionthe disadvantages referred to above.

It is a. further object of the invention to provide an improvedapparatus of the kind referred to which comprises a structure mounted torotate about a horizontal or inclined axis, means integral with saidstructure to provide a closed heli- 55 taining the carrier bodiestherein. 'I'he said apparatus maybe constructed as a unit for use inconjunction with a kiln, such as a rotary cement kiln, (working oneither the wet or dry process of cement manufacture) or the apparatusmay be mounted within the feed end of a rotary kiln or in an enlargedextension thereof. In all cases when used in the manufacture of cementthe exhaust gases from the kiln are preferably employed to dry thematerial, although it will be appreciated that when the apparatus isemployed (for example as a separate unit) for drying other materialsother heating or drying gases or medium may be used.

Further the channel or .compartment may be divided along its length intoa number of subcompartments each having lling or` carrier bodiesdisposed therein, the sub-compartments being preferably formed by curvedgrids or webs of perforated form, enabling the material to passfrom onesub-compartment to another but retaining the carrier bodies therein.Alternatively, the sub-compartments may be omitted and the carrierbodies and the material to be dried may pass simultaneously from one endvof the said channel to the other and at the discharge end the materialdried may pass to a suitable foutlet whilst the carrier bodies may bedischarged into a central-ly disposed channel Where they are conveyed tothe feed end of the said channel. i

In order that the said invention may be clearly understood and readilycarried into eiect, the same will now be more fully described withreference to the accompanying drawings in which:.

Figure 1 is an elevation partly in longitudinal section of an apparatusconstructed in accordance with the preferred form of the' invention;

Figure 2 is a cross-sectional view on the line 2-2 of Figure 1;

Figure 3 is a diagrammatic View illustrating another examplev of theinvention; 4

Figure 4 isla diagrammatic View illustrating a. modication of theconstruction shown Ain Figure 3;

Figures 5 and 6 are respectively cross-sectional views taken along thelines 5--5 and G--G of Figures 3 and 4 respectively. l

Referring now more particularlyto Figures 1 and 2 of the accompanyingdrawings which illustrate a form of the invention for use by way ofexample with an apparatus for drying cement slurry, the referencenumeral li indicates a substantially cylindrical casing supported forrotation on bearings l2 about anaxis slightly inclined to thehorizontal. The apparatus shown in Figures 1 and 2 is adapted to beemployed in conjunction with a cement kiln for which purpose thedischarge end I3 of the casing I I is adapted to be rigidly connectedwith the feed end of a rotary kiln not shown which rotates with thecasing II. 'I'he exhaust gases from the kiln inL the example shown areutilized for the purpose of drying the the casing II is formed toprovide a helical passage for the flow of the drying gases, the dryinggases thus passing axially from one end of the casing II to the otherfollowing the helical path formed in the said casing. As shown thehelical path is constituted by the provision of a wormlike vane I6,which may be composed of a plurality of plates suitably connectedtogether as shown, which extends from the inner surface of the casing IIto which the outer edges of the worm-like vane are connected whilst theinner edges of the said vane are connected to a central support I1. Thechannel or compartment formed by the worm-like vane I6 is divided into anumber of sub-compartments by the provision of substantially radiallydisposed grids I8 extending from the central support AI1 to the innersurface of the casing II. The grids may be formed of perforated materialalthough in the example shown the grids comprise a series of barssuitably secured in position. 'I'he said grids are preferably curved asshown with the concave surfaces thereof facing the direction of rotationindicated by the arrow in Figure 2. In the example shown in the drawingsfour sub-compartments indicated by the reference numerals I 9 areafforded by the grids I8. One of the grids I8 is disposed at thecommencement of-the said helical path whilst another grid is disposed atthe end thereof. Each sub-compartment I8 is partially filled with llingor carrier bodies as shown in Figure 2 the' grids I8 being so formed asto retain the filling or carrier bodies in the subcompartments butpermitting of the passage of the dried or partially dried slurry fromone compartment to another.

The carrier or lling bodies in all examples of the invention may be ofany suitable construction and they may comprise solid bodies of anysuitable form, such as spherical, cylindrical or the like, oralternatively they may be hollow cylinders which may, if desired haveapertures in -the walls thereof, orthey may be ring shaped elements orotherwise according to requirements. Also, if desired, the said bodiesmay comprise chains which may or may not be connected to the saidcompartments. Also the carrier bodies may comprise helices ofrectangular or other suitable shape in cross-section. Due to theprovision of the subcompartments .the lling or carrier bodies y thereinare disposed about the axis f the casing II so that the -carrler bodiesin the several subcompartments substantially counterbalance one anotherduring rotation of the casing, thus avoiding the unbalanced loadhereinbefore referred to. As above mentioned the material to be dried isfed into the end I4 and during rotation of the casing II the materialpasses through the first grid I8 into contact with the filling orcarrier bodies therein which become coated with the slurry whilst thedrying gases entering the end I3 of the casing flow through the helicalchannel drying the slurry which is coated on the said bodies. Duringrotation the carrier bodies constantly change their relative positionsdue to the cascading action which occurs, contact with one another andserve to prevent a caking or agglomeration of the material which isdislodged from the bodies and passes through the successivesub-compartments to the filling or carrier bodies therein and is finallydischarged through the last grid I8 whence it passes through thedischarge end I3 directly into the kiln for further treatment. Theseveral subcompartments maintain a. mass of carrier or lling bodies inthe path of the drying gases so as effectively to dry the materialadhering to or intermingling with the carrier or filling bodies. In theexample shown the drying gases flow in an opposite direction to that ofthe slurry flow although it is to be appreciated that if desired thedrying gases may iiow in the same direction as the slurry. The provisionof the helical channel constituted by the vane I6 causes the materialfed in at the end I4 to progress positively from such end to thedischarge end of the helical channel. Man-holes 20 may be provided alongthe length of the casing I I for inspection purposes or for insertingthe carrier bodies in the several sub-compartments whilst the dischargeend of the casing II may be provided with a lining of refractorymaterial indicated by the reference numeral 2 I.

Figures 3 to 6 of the accompanying drawings illustrate diagrammaticallymodified constructions of the apparatus shown in Figures 1 and 2 themain distinction being that the radial grids I8 are omitted and thecarrier bodies and the slurry progress simultaneously along a helicalchannel, at the discharge end of which the slurry and the lling crcarrier bodies are separated the said bodies being returned to the feedend of the said channel. -In these figures the reference numeral 22indicates a solid worm-like vane extending port 24. The material to bedried is introduced through a nozzle 25 situated at one end of thecasing 23, the material introduced and the carrier bodies beingpositively progressed by the action ofthe vane 22, during rotation ofthe casing from the feed end to the discharge end of the casing, whichlatter may be directly connected to` a rotary kiln 26.-v In the exampleshown the exhaust gases from the kiln 26 are utilized to dry thematerial and due to the provision of the helical passage formed by theworm 22 the drying gases must pass through .the mass of carrier bodiesbefore reaching the outlet at the feed end of the casing 23. At thedischarge end of the helical channel a grid 21 is provided extendingbetween a plate 21a and the end of the vane 22 which grid is ofsufficient size to permit the passage of the dried material butpreventing the passage of the carrier bodies. By the time the carrierbodies and the material reach the grid 21 the material is sufficientlydried to become dislodged from the carrier bodies by the relative actionof the bodies as they are progressed by the vane 22 the dislodged ordried material passing through the grid 21 directly into the kiln 26whilst the carrier bodies during rotation of the casing 23 pass throughan opening 28 in the hollow central support 24 Where they are conveyedthrough the hollow support by means of a suitably constructed worm orother conveyor 24a 75 and discharged through an opening 29 at the feedend of the casing. The carrier bodies discharged from the opening 29 arein a heated condition in 'I which state they become again coated withcold slurry fed through the nozzle 25.A In this example the material andthe carrier bodies are progressively moved from one end of the casing 23to the other during which movement the material is subjected to theaction of the drying gases which flow axially of the casing 23Afollowing the helical path defined by the Worm 22 and when the grid 21is reached the material passes into the kiln 26 whilst the carrierbodies are conveyed to the commencement of the helical path asaforesaid.

Figures 4 and 6 of the drawings illustrate a similar but slightly modiedconstruction in which the centralsupport 24 instead of being ofcylindrical form as in Figure 3,-is of a conical form with the smallerend disposed at the discharge end of the casing 23. 'I'he generalconstruction and operation of the apparatus shown in Figures 4 and 6 issimilar to that described with reference to Figures 3 and 5.

In the embodiments illustrated the material to be dried is fed toextensions of the respective casings which form troughs from which thematerial passes into the helical channel. In Figures 1 and 2 the troughis formed by the conical wall Il la and in Figures 3 to 6 by the wall23a.

Since the drying gases must pass through the mass of carrier bodiesbefore reaching the outlet any cement dust carried along by the gases isabstracted by the slurry coated bodies.

Whilst the examples of the invention described above are adapted torotate with a rotary kiln it will be understood that if desired theapparatus may be constructed as a unit for use independently of or inconjunction with a kiln or with any other apparatus, or alternativelythe apparatus may be mounted in the feed end of a kiln orA co-axiallywith the kiln and rotated independently thereof, in which latter casethe drying apparatus may be connected to the feedl end of the kilnthrough the medium of a suitable gland to prevent the escape of the kilngases.

What I claim and desire to secure by Letters Patent of the UnitedStates, is:

1. Apparatus for drying slurry and other materials comprising astructure mounted to rotate about an axis disposed at an angle to thehorizontal, means integral with said structure to provide a closedhelical or spiral channel therein, along which `a drying medium isconstrained to flow, carrier bodies in the channel to'which the'materialto be dried is fed and means for separating the dried material and thecarrier bodies to enable the dried material to be discharged from saidstructure whilst retaining the carrier bodies therein.

2. Apparatus for drying slurryand other materials comprising a structuremounted to rotate about an axis disposed at an angle to the horizontal,means integral with said structure to provide a closed helical or spiralchannel therein, along which a drying medium is constrained to flow,`means to divide said channel into a plurality of sub-compartments, andl carrier bodies in said sub-compartments to which` the material to bedried is fed.

3. Apparatus for drying slurry and otherma- .terials as claimed in claim2, in which the subcompartments are substantially radially disposed.

4..Apparatus for drying slurry or other materials comprising a structuremounted to rotate about an axis disposed at an angle to the horizontal,means integral with said structure to provide a closed helical or spiralchannel therein along which a drying medium is constrained to flow, aplurality of substantially radially disposed grids in said channeldividing the same into a number of sub-compartments, and carrier bodiesin said sub-compartments to which the material to be dried is fed. l

5. Apparatus for drying slurry and similar materials as claimed in claim4, in which the grids are curved, the concave faces thereof projecting6. Apparatus for drying slurry and similar materials comprising astructure mounted to rotate about an axis disposed at an angle to thehorizontal, a hollow support within said structure having an inlet andan outlet, a Worm-like vane mounted on said support and rigidly securedto the structure to form a closed helical channel, carrier bodies withinthe channel to which the material to be dried is fed, said carrierbodies being progressed simultaneously with said material along thestructure from one end to the other, means for separating the carrierbodies and the dried material to enable the said dried material to bedischarged from the structure whilst retaining the carrier bodiestherein conveying means within said hollow support for causing thecarrier bodies to be conveyed from the inlet of said support to theoutlet thereof, and means for returning said carrier bodies to the inletof said hollow support.

7. Apparatus for drying slurry as claimed in claim 6, wherein the hollowsupport is cylindrical.

8. Apparatus for drying slurry and similar materials as claimed in claim6, wherein the hollow support is of a conical form with the smaller enddisposed inthe vicinity where the carrier bodies and the material areseparated.

9. In a rotary kiln, a drying zone for material `to be burnt in saidkiln, means mounted within said zone to provide a closed helical orspiral channel therein along which gases from said kiln `are constrainedto ilow in countercurrent to thel material to be dried, means dividingsaid channel into a plurality of sub-compartments, and carrier bodies insaid sub-compartments to which the material to be dried is fed.

10. A rotary kiln having a drying zone for ma.- terial to be calcined inthe kiln, characterized by the provision in'the drying zone of a helicalchannel with loose bodies of heat-resistant material therein and aperforated wall preventing the passage of the bodies from the channelinto the body of the kiln but 'allowingythe kiln gases to pass throughthe channel in countercurrent to the material.

11. A rotary kiln according to claim 10, in which the helical channel isdivided into a number of sections by perforated walls with a charge ofloose bodies of heat-resistant material.

12. A rotary kiln according to claim 10, in which the partition, formingthe walls of the helical channel rotates with the kiln.

nonni. DOUGLAS PARKER.

Vin the direction of rotation of the said structure.

